1. Field of the Invention
This disclosure relates generally to an isolation system for oil and gas wells and, more particularly, to a formation isolation system comprising a first integral and actuatable isolation device and a second isolation device.
2. Description of the Related Art
A typical hydrocarbon well may utilize one or more gravel packs and screen assemblies to enhance production from, for example, unconsolidated formations. It is desirable in such wells to isolate each producing formation using a variety of flow control devices, such as packers and valves. It is also desirable to provide bi-directional isolation and interventionless actuation, such as interventionless opening, of one or more of the isolation devices. It is not unheard of, however, for the interventionless or mechanical actuation system to become fouled and unusable. In such circumstances, the isolation device, such as, for example, a ball valve, may need to be be drilled or milled out of the completion string. Such fouling and recovery efforts are obviously undesirable.
This application for patent discloses an improved isolation system and method of use comprising a first isolation device that is integral with the system, such as a pressure actuated valve or mechanically actuated valve, and a second isolation device, such as a plug, so that when both devices are closed, the formation is isolation and when the first device is open and the second device is closed, the formation is not isolated.